| Grefrath to Obernburg am Main | 160.55 mi (258.37 km) |
| Grefrath to Obernkirchen | 134.92 mi (217.14 km) |
| Grefrath to Oberschleissheim | 315.77 mi (508.19 km) |
| Grefrath to Oberstdorf | 323.93 mi (521.31 km) |
| Grefrath to Obertraubling | 305.41 mi (491.50 km) |
| Grefrath to Obertshausen | 139.96 mi (225.24 km) |
| Grefrath to Oberursel | 125.19 mi (201.48 km) |
| Grefrath to Ochsenfurt | 200.95 mi (323.40 km) |
| Grefrath to Ochsenhausen | 277.14 mi (446.01 km) |
| Grefrath to Ochtrup | 70.19 mi (112.96 km) |
| Grefrath to Odenthal | 39.59 mi (63.72 km) |
| Grefrath to Oelde | 84.92 mi (136.67 km) |
| Grefrath to Oelsnitz | 261.74 mi (421.23 km) |
| Grefrath to Oer-Erkenschwick | 44.49 mi (71.60 km) |
| Grefrath to Oerlinghausen | 108.80 mi (175.10 km) |
